Sources for Carbon Fiber sheets (weaved, ready for resin)?

[Jordo _99]

I've seen a few people making sheaths and other materials out of carbon fiber and I'm wondering if there's a source out there that I should look for?

I'm specifically looking for 1k or 3k sheets as I'd be making molds for tiny cycling and outdoor bits and prototypes.

The place that came up on google first shows $250 for a 42"x36" sheet of 1k…seems overpriced at $24/sqft?

-Jordan

[Colin Krusor]

Jordan, ebay has multiple listings for 3k plain weave carbon fiber cloth for less than 1/10th of the price you found. I have also found half a dozen or more other suppliers online using google.

Have you decided exactly what kind of carbon fabric you need? 4 harness satin? Twill? Plain weave? If you plan to lay up bike parts with complex curves you'll need (or wish you had) a vacuum setup and satin weave cloth (not plain weave). Try searching google or ebay with more specific terms and appropriate jargon ("cloth" rather than "sheets").

[Jordo _99]

I'm not positive about the weave I need. The items I'm making around going to need to be weight baring so much…stuff like a "race number holder" for my bike and probably an UL eating utensil…things of that nature. I'm not terribly interested in the weight savings of 1k as I am the smaller weave which (I believe) will work better for very tight bends in the fabric.

Searching for cloth helped a lot and I ended up finding a starters kit as well as some cool looking (and cheap) carbon/kelvar weaves which should be interesting as well.

Thanks for the help though. I'll probably just get a kit for starters and go from there if I enjoy it enough.

[Mike In Socal]

Jordan,
Check out CST Sales

Mike

[Colin Krusor]

Yes, as Mike said, CST sales is one vendor with a decent selection, although I've found that their prices are higher than some others.

Also, for an UL eating utensil, keep in mind that no common epoxy is food-grade. There are two that I know of that are, but they are obscure, expensive, and have poor mechanical properties. Also, some common epoxies soften quite a bit at boiling water temperatures. So, for the utensil, my recommendation is to use an epoxy that withstands higher temperatures, and then give the utensil a final coating with something (like a silicone) that is food safe.

[Dan Yeruski]

Does Locura sell fabric and epoxy? Any idea what the weight per yard is that he uses on his lids(threads per inch) Has he published a msds sheet on his lids? Wonder if he uses the same epoxy as his other items.

[Colin Krusor]

Dan, Josh at Ruta Locura doesn't advertise any composite layup supplies on his website. I don't know if he'd be willing to sell any of it.

I made a carbon/kevlar composite lid for my cookpot using supplies I bought from vendors online. When I was doing some early experimenting prior to that project I found that two layers of 5oz plain weave 3k carbon cloth is plenty strong for a pot lid if you treat it carefully.

Threads per inch is not a common way to describe carbon cloth for composite reinforcement (it is used for kevlar and fiberglass, sometimes). For carbon, the convention is to note the number of filaments per tow (1k, 3k, 6k, etc.), the weave type (plain, twill, satin, etc.), and the areal density (5oz, 14oz, etc.).

Forgive me if you know this stuff already. Just noticed your use of threads per inch in your post and thought this info might be helpful.

[Dan Yeruski]

I thought Josh may have given that info out at one time when I think I had heard he was no longer making the lids.

Maybe it's "tow" per inch :-)

Why did you use 2 layers of cloth instead of choosing a single layer of a thickness 2x that of the material you used? I guess a sheet of 3k instead of 2 sheets of 1k would work? dunno!

Yes, your info was helpful….thank you! I'm new to this DIY fabrication.

[Dan @ Durston Gear]

Interesting information. I didn't realize working with CF was within reach of the garage MYOG'er.

[Colin Krusor]

Yes, it's fairly easy to lay things up in carbon fiber. I posted about several items I made, including this knife sheath:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=77619

The investment to get started doing hand layup of carbon fiber is about $30 in epoxy, $35 in carbon cloth, and $30 in other incidental stuff (a roller, tape, masking plastic, foam, clamps, etc). That amount of material would provide for lots of projects.

Dan Y., I would recommend using a minimum of two (three is better) layers of reinforcement for two reasons. First, it ensures that no epoxy-only voids in the weave of the reinforcement will penetrate through the entire thickness of the part. If you hold a part made with a single layer of heavy cloth up to the light, you'll see spots of light arranged in a grid where there are gaps in the weave of the cloth. Carbon fiber reinforcement cloth tends to be very loosely woven to avoid air entrapment (to permit the epoxy to fill all the spaces). If you use more than one layer of lighter cloth, any epoxy-filled voids in the weave will be shallow (and reinforced by carbon under or over it). Second, using more than one layer of lighter cloth allows you some flexibility in the way you design the reinforcement. You can align the layers so all the reinforcement goes in two directions, or you can rotate them so you have reinforcement in 4, 6, 8, or more directions.

[Dan Yeruski]

I think I'll have to give it a try. I'll use your suggestions and see how it goes.

You say you wrapped the knife sheath in PE film before compressing it. What is PE film?

[Colin Krusor]

PE = polyethylene. A piece cut from a kitchen garbage bag.

[Tanner M]

> Has he published a msds sheet on his lids?

I don't suppose it would hurt to ask but I doubt he would have an MSDS for an article. It isn't intended to be heated to the point of melting or releasing a fume. It won't be ground or etc. It isn't likely to be any more hazardous than a tripod leg. Except it is being used to cover a pot.

I figure you ask because of the other comment about food grade epoxies or silicone coating. I really don't know if there is any kind of certification for cooking stuff. I never paid attention when I have bought cookware.

[Dan Yeruski]

Hello Tanner,
In my research I found that there is a food grade epoxy for use with carbon fiber fabric. With all the hullabaloo about leaching chemicals I was curious about it's use.

I used to work in the screen printing industry. We printed inks on flame treated 1/4" thick polyethelene sheets. The flames eliminated whatever it was that prevented the ink from sticking. We flame treated and then had to print the sheets on the same day before the chemicals would leach out. If we waited 24 hours the ink adhesion was splotchy over the entire sheet. 48 hours and the complete sheet was non printable due to leaching and had to be flame treated(gas fired) again.

Pot lids heated to 212 degrees could surely have some epoxy goodies leach out. If I were to make my own pot lids I would want the food grade stuff.

A friend of mine had his own printing company and did lots of printing on metal sheet. He used epoxy ink. He became allergic to the catalyst used and had to stop using that type of ink. He switched to an ink cured with ultraviolet light. To this day his skin on his hands is dry and cracked and are not a good sight for sore eyes.

[Colin Krusor]

Dan, what is the name of the food-safe epoxy you found?

There are two FDA standards for food-grade materials. The less stringent standard is FDA CFR 175.105. An epoxy that meets this standard is considered safe for incidental or indirect contact with foods, but cannot be used for food containers or contact with food at elevated temperatures. The more stringent standard is FDA CFR 175.300. This standard is for materials that will be in direct contact with food or any contact with heated food.

There are quite a few epoxies (almost all of them designed for coating applications, not composites) from several companies that meet the FDA CFR 175.105 standard. There are a smaller number of coating (not composite) epoxies that meet the FDA CFR 175.300 standard, but Adtech EL-300 is the only epoxy I know of that meets FDA CFR 175.300 and can be used for composite layup. All of these are an order of magnitude weaker than the best (non-food-safe) composite epoxies.

[Dan Yeruski]

Colin, this is the one I came across a couple of times mentioned on forums etc:

Master Bond Polymer System EP42HT-2FG is a room temperature setting, two component epoxy adhesive, sealant and coating specially formulated for food applications.

I'm sure that the manufacture advises following the direction to the letter.

I don't think I found an over the counter supplier in small quantities.

[Tanner M]

Other than a requirement developed for cooking stuff (maybe by FDA but I really have no clue), the fellow might have a Product Data Sheet. I doubt even that… You may know, but Product Data being more about constraints in use, concentrations, or whatever. In contrast to MSDS.

Companies that manufacturer very processed food ingredients that really do need an MSDS really don't like to release one. I can see their point. An MSDS for food ingredients just sounds unwholesome. MSDS aren't required for food as you might use it at home. Some commercial bakeries… factories use things that need MSDS even if it is a 'natural' flavoring. Not talking about vinegar and things that are generally recognized to be able to cause injury…

Anyway, I certainly see your point. It is a valid concern. Just saying you might need a little different approach to get your answer as I doubt he will like to discuss leaching and etc. I could be wrong. However, if he used food grade stuff, I imagine he would bang a drum..?

[Colin Krusor]

Dan, I've used Masterbond EP42HT-2FG as a coating for a water bath in the lab. Masterbond EP42HT-2FG is essentially a translucent amber paint. It is one of a dozen or more coating epoxies that I know of that meet the FDA 175.300 standard.

If you saturated some carbon cloth with Masterbond EP42HT-2FG, you'd get a composite, but it would be much weaker than one made with Adtech EL-300, which was designed for composites and is mechanically strong once cured (and also meets the FDA 175.300 standard).

I have no criticisms of Josh at Ruta Locura, but I imagine that the epoxy he used for his lids is a standard (non food-grade) epoxy like one of the West System combinations or Aeropoxy products. Those companies say in their literature that they cannot and will never recommend their epoxies for food or potable water containers, but, as I said, I wouldn't fault Josh if he used these or something similar. I think the risk to users is small, and (importantly) the small risk is well known, so users can make their own decisions. My decision would be to coat it with silicone or use a FDA 175.300 compliant epoxy, but most other users might not worry about it.

[Tanner M]

Good. Thanks.
Mmm, for some reason, I missed your post that preceded my earlier one… I see, now. FDA 175.300

[Dan Yeruski]

When I wear Latex gloves I get an allergic reaction on my skin. Nitrile is user friendly. Using food grade epoxy might be the best for me. Asking a question about R. Lucura was to get a product name off the msds sheet, no criticism intended.

A bit of info found in my research showed that using too much catalyst will cause an improper hardening and will leach more readily when heated.

I agree that most users won't worry about the the leaching just as most people don't worry about smoking or use of alcohol.

My concerns were for ME. Mixing the chemicals and then machining the end product.

Using Masterbond EP42HT-2FG might be strong enough for a 4" diameter pot lid but not for something else.

Thanks for your help everyone. Mission accomplished.

[Author]

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